Semiconductor device comprising a Schottky barrier diode

Abstract

The present invention aims to enhance the reliability of a semiconductor device equipped with a Schottky barrier diode within the same chip, and its manufacturing technology. The semiconductor device includes an n-type n-well region formed over a p-type semiconductor substrate, an n-type cathode region formed in part thereof and higher in impurity concentration than the n-well region, a p-type guard ring region formed so as to surround the n-type cathode region, an anode conductor film formed so as to integrally cover the n-type cathode region and the p-type guard ring region and to be electrically coupled thereto, n-type cathode conduction regions formed outside the p-type guard ring region with each separation portion left therebetween, and a cathode conductor film formed so as to cover the n-type cathode conduction regions and to be electrically coupled thereto. The anode conductor film and the n-type cathode region are Schottky-coupled to each other.

What is claimed is: 
     
       1. A semiconductor device comprising:
 (a) a semiconductor substrate of a first conductivity type; 
 (b) a first semiconductor region of a second conductivity type corresponding to a conductivity type opposite to the first conductivity type, the first semiconductor region being formed in the semiconductor substrate; 
 (c) a second semiconductor region of the first conductivity type, the second semiconductor region being formed in the semiconductor substrate within the first semiconductor region; 
 (d) a third semiconductor region of the first conductivity type, the third semiconductor region being formed in the semiconductor substrate within the second semiconductor region; 
 (e) a first conductor film formed over the semiconductor substrate so as to integrally cover the first semiconductor region, the second semiconductor region, and the third semiconductor region provided thereinside and to be electrically coupled to the first semiconductor region and the third semiconductor region, respectively; 
 (f) a first conductive portion electrically coupled to the first conductor film; 
 (g) a first insulating film formed over the semiconductor substrate, the first insulating film being formed so as to surround the third semiconductor region in a plan view; 
 (h) a fourth semiconductor region of the second conductivity type, the fourth semiconductor region being formed outside the third semiconductor region within the first semiconductor region with the first insulating film remaining therebetween; 
 (i) a second conductor film formed in the semiconductor substrate so as to cover the fourth semiconductor region and to be electrically coupled to the fourth semiconductor region; 
 (j) a second conductive portion electrically coupled to the second conductor film; and 
 (k) a fifth semiconductor region of the second conductivity type, the fifth semiconductor region being formed in the semiconductor substrate within the first semiconductor region, 
 wherein electrical coupling of the first semiconductor region and the first conductor film is Schottky coupling, 
 wherein the second semiconductor region and the third semiconductor region are formed at an end of the first conductor film in the first semiconductor region, 
 wherein an impurity concentration of the third semiconductor region is higher than an impurity concentration of the second semiconductor region, 
 wherein the second semiconductor region extends into the first semiconductor region more than the first insulating film, 
 wherein the third semiconductor region extends into the first semiconductor region less than the first insulating film, 
 wherein the second semiconductor region, the third semiconductor region, and the fourth semiconductor region are formed in the fifth semiconductor region, and 
 wherein an impurity concentration of the fifth semiconductor region is higher than an impurity concentration of the first semiconductor region. 
 
     
     
       2. The semiconductor device according to  claim 1 ,
 wherein the semiconductor substrate comprises a semiconductor material comprised principally of silicon, and the first conductor film is a material comprised of a compound of silicon and a metal element. 
 
     
     
       3. The semiconductor device according to  claim 1 , further including:
 a sixth semiconductor region of the first conductivity type, the sixth semiconductor region being formed outside the first semiconductor region; 
 a third conductor film formed so as to cover the sixth semiconductor region and to be electrically coupled to the sixth semiconductor region; and 
 a third conductive portion electrically coupled to the third conductor film, 
 wherein an impurity concentration of the sixth semiconductor region is higher than an impurity concentration of the semiconductor substrate. 
 
     
     
       4. The semiconductor device according to  claim 3 ,
 wherein the sixth semiconductor region is formed so as to surround the first semiconductor region in the plan view. 
 
     
     
       5. The semiconductor device according to  claim 1 ,
 wherein a plurality of field effect transistors are formed over the semiconductor substrate. 
 
     
     
       6. The semiconductor device according to  claim 1 ,
 wherein the first conductive portion is formed so as not to overlap the second semiconductor region and the third semiconductor region in the plan view. 
 
     
     
       7. The semiconductor device according to  claim 1 ,
 wherein the third semiconductor region is in direct contact with the first insulating film. 
 
     
     
       8. The semiconductor device according to  claim 1 ,
 wherein the fourth semiconductor region is in direct contact with the first insulating film. 
 
     
     
       9. The semiconductor device according to  claim 1 ,
 wherein the first insulating film is formed by embedding an insulation film into a trench formed in the semiconductor substrate.